LOW TEMPERATURE SPLIT INJECTION SPRAY COMBUSTION: IGNITION, FLAME STABILIZATION AND SOOT FORMATION CHARACTERISTICS IN DIESEL ENGINE CONDITIONS

The aim of the PhD work is to investigate the fundamental differences in combustion behavior when split injections are used in low temperature combustion regime. In this thesis, the first injection is also called as pilot injection and second injection is also called as main injection. The broad aspects which are studied encompassing the investigation is to study the ignition delay, lift-off and soot formation of such a double split spray combustion. The mechanisms of ignition, lift-off and soot production are to be studied since the main ignition and lift-off were found to differ from the pilot which effect net soot production. The planned studies in the present work are divided into 1) experimental and 2) numerical approaches. Experimental approach involves high-speed schlieren and luminosity imaging to visualize the spray/flame progress and qualitative soot formation respectively. This is often coupled in a simultaneous way to the laser-based planar laser induced fluorescence (PLIF) technique to visualize ignition behavior in terms of formaldehyde presence and soot precursor visualization of poly-cyclic aromatic hydrocarbons (PAH). As part of CFD simulations, thorough validations of the fuel liquid length, vapor (mixture) presence, temporal and spatial species (formaldehyde, soot) presence, ignition delay, lift-off length, and heat release rate are performed. The main objective of the proposal work would be to perform experimental research with split injection strategies, simulate them using CFD and then understand the underlying mechanisms of important processes of ignition, lift off mechanisms in subsequent injections and the associated soot production mechanisms

Study the effect of metal ion on wool fabric dyeing with tea as natural dye

AbstractAqueous extract of natural dye, tea was dyed on the wool fabric with dark brown for 2% and 5% shade. The tea containing tannins as the main colorant species to produce different shade with different mordant salts. The mordant salts Alum, CuSO4, FeSO4, ZnSO4, Na2SO4, and MgSO4 were used to dye fabric using three different dyeing methods: pre-mordanting, meta-mordanting and post-mordanting. The color of the fabric was investigated on Data Color matching system in terms of K/S and CIE Lab-color difference values. The post-mordanting method gave the great depth of shade of natural dye tea with 2% and 5% shade, it also give good light fastness and wash fastness properties. Copper was found as a good mordant to achieve the best results with transition metal ions effect. Deep shades (K/S=17.50) were obtained for original sample of 5% with color difference ΔE value is 0.17, as compare to 2% original sample of tea of light brown shades (K/S=10.50) with color difference ΔE value is 0.50 under maintained temperature at 85°C for 35min of dyeing

ANALYSIS AND DESIGN OF PRE - ENGINEERED STEEL BUILDING FOR AIRBUS A-380 HANGAR USING IS CODES

The pre-engineered steel framed structure (PEB) introduced in 1960’s includes a structural frame, roofing system and wall supports; for the construction of industrial structure like ware houses, car showrooms, workshops, function halls, stadiums, aircraft hangars etc. is found to be economical, light weight and fast erection process. The PEB’s are built to perform some important functions, provide enough space for storing goods; aircrafts etc.. and protecting the storage items against natural disasters, wind forces, and rain. In this research work a hangar for airbus A-380 has been designed considering its dimensions; for maximum span of 120M and width of 115M and a height of 30M as a pre-engineered framed structure. For designing the structural members staad pro (V8i) software is used. This structural design is in accordance with the specification of the general construction in steel confirming to IS:800-2007 (limit state design) and wind application as per latest code confirming to IS:875-2015 ( part-III) and earthquake analysis has been done as per IS-1893-2016 (part-IV). For the first time a hangar for A-380 has been designed for using above IS Codes, structural design details, connection details have been produced and found that the total steel is 3502.43 Metric Tons

Prospective comparison of point-of-care device and standard analyzer for monitoring of international normalized ratio in outpatient oral anticoagulant clinic

Point-of-care testing (POCT) coagulometers are increasingly being used in the hospital setting and patients’ self-testing. We determined the agreement of prothrombin time international normalized ratio (INR) results by POCT coagulometer and laboratory instrument through a comparative analysis and investigated whether the results of POCT coagulometer can reliably be used without being confirmed by standard laboratory analyzer. A total of 200 INR measurements by POCT coagulometer (CoaguChek XS Pro) and laboratory analyzer (Sysmex CS2000i) were compared using Passing-Bablok regression analysis and Bland-Altman plot. Agreement of the INR measurement was further analyzed in relation to dosing decision. The correlation of INR measurements between CoaguChek XS Pro and Sysmex CS2000i was excellent (correlation coefficient ¼ 0.973). The overall mean difference was 0.21 INR + 0.32 (range: 1.7-0.44). The mean difference was found to get increased as INR results increased and was 0.09 in the subtherapeutic range (1.9 INR), 0.29 INR in the therapeutic range (2.0-3.0 INR), while 0.4 INR in the supratherapeutic range (\u3e3.0 INR). The overall agreement was excellent (k ¼ 0.916) and overall 11 (5.5%) of 200 INR measurements showed a difference in dosing decision between the 2 instruments. The positive bias of POC-INR is evident in the supratherapeutic range which could affect the dosing decision requiring confirmation with the laboratory INR measurement

Ignition Process and Flame Lift-Off Characteristics of dimethyl ether (DME) Reacting Spray

Advanced combustion systems that utilize different combustion modes and alternative fuels have significantly improved combustion performance and emissions compared to conventional diesel or spark-ignited combustions. As an alternative fuel, dimethyl ether (DME) has been receiving much attention as it runs effectively under low-temperature combustion (LTC) modes such as homogeneous charge compression ignition (HCCI) and reactivity control combustion ignition (RCCI). Under compression-ignition (CI), DME can be injected as liquid fuel into a hot chamber, resulting in a diesel-like spray/combustion characteristic. With its high fuel reactivity and unique chemical formula, DME ignites easily but produces almost smokeless combustion. In the current study, DME spray combustion under several different conditions of ambient temperature (Tamb = 750–1100 K), ambient density (ρamb = 14.8–30 kg/m3), oxygen concentration (O2 = 15–21%), and injection pressure (Pinj = 75–150 MPa) were studied. The results from both experiments (constant-volume combustion vessel) and numerical simulations were used to develop empirical correlations for ignition and lift-off length. Compared to diesel, the established correlation of DME shows a similar Arrhenius-type expression. Sensitivity studies show that Tamb and Pinj have a stronger effect on DME\u27s ignition and combustion than other parameters. Finally, this study provides a simplified conceptual mechanism of DME reacting spray under high reactivity ambient (high Tamb, high O2) and LTC conditions. Finally, this paper discusses engine operating strategies using a non-conventional fuel such as DME with different reactivity and chemical properties

HIV prevalence in blood donors and recipients in Pakistan: a meta-analysis and analysis of blood-bank data

Background: The first instances of HIV-antibody detection in donated blood in Pakistan were reported in 1988. Since then, documentation of HIV in blood donors and of rates of transmission via transfusion has been limited. Previously assumed to have a low prevalence, HIV is an increasing health concern in Pakistan. Since there is no national, centralized blood-banking system, there are no reliable data on which to base estimated risks of transfusion-associated HIV infection. This study was therefore conducted to estimate the prevalence of HIV in blood donors and recipients in Pakistan between 1988 and 2012. Methods: Meta-analyses were undertaken of reported prevalences of HIV in blood donors and recipients published during 1988-2012. Papers were identified by searching PubMed, Google, CINAHL and PakMediNet and the websites of the World Health Organization, the national HIV/AIDS Surveillance Project and the National AIDS Control Programme of Pakistan. In addition, the 1998-2012 records of the Aga Khan University blood bank were analysed. Results: The 254 abstracts identified at the preliminary search were reviewed and, after removal of duplications, case-reports, editorials and reviews, 32 papers were selected that met the inclusion criteria. All studies that reported on HIV antibodies in blood donors/recipients were included, irrespective of the methodology used. Since seroconversion had only been confirmed through supplemental testing in a few papers, the results were analysed separately for reports based on screening only and confirmed cases. A total of 142 of 2 023 379 blood donors and 4 of 3632 blood recipients were HIV positive, giving an overall pooled seroprevalence of 0.00111% in blood donors and 0.00325% in blood recipients. The annual prevalences of HIV in donors at the Aga Khan University blood banks were similar, ranging from 0.013% to 0.116%. Conculsion: Very few reports on HIV in blood donors in Pakistan could be retrieved, and the overall pooled prevalence is low. However, the limited data and confounding factors mean that that these results may significantly underestimate the true situation. It is recommended that a complete survey of blood banks should be conducted throughout the country, in order to provide a more reliable estimate of the risk of transfusion-associated HIV infection in Pakistan

Neonatal hyperbilirubinemia in infants with G6PD c563C \u3e T variant

Background: There is a strong correlation between glucose-6-phosphate dehydrogenase (G6PD) deficiency and neonatal hyperbilirubinemia with a rare but potential threat of devastating acute bilirubin encephalopathy. G6PD deficiency was observed in 4–14% of hospitalized icteric neonates in Pakistan. G6PD c.563C \u3e T is the most frequently reported variant in this population. The present study was aimed at evaluating the time to onset of hyperbilirubinemia and the postnatal bilirubin trajectory in infants having G6PD c.563C \u3e T. Methods: This was a case–control study conducted at The Aga Khan University, Pakistan during the year 2008. We studied 216 icteric male neonates who were re-admitted for phototherapy during the study period. No selection was exercised. Medical records showed that 32 were G6PD deficient while 184 were G6PD normal. Each infant was studied for birth weight, gestational age, age at the time of presentation, presence of cephalhematoma, sepsis and neurological signs, peak bilirubin level, age at peak bilirubin level, days of hospitalization, whether phototherapy or exchange blood transfusion was initiated, and the outcome. During hospital stay, each baby was tested for complete blood count, reticulocyte count, ABO and Rh blood type, direct antiglobulin test and quantitative G6PD estimation [by kinetic determination of G6PDH]. G6PDgenotype was analyzed in 32 deficient infants through PCR-RFLP analysis and gene sequencing. Results: G6PD variants c.563C \u3e T and c.131 C \u3e G were observed in 21 (65%) and three (9%) of the 32 G6PD deficient infants, respectively. DNA of eight (25%) newborns remained uncharacterized. In contrast to G6PD normal neonates, infants with c.563C \u3e T variant had significantly lower enzyme activity (mean ± 1SD; 0.3±0.2 U/gHb vs. 14.0±4.5 U/gHb, p\u3c0.001) experienced higher peak levels of total serum bilirubin (mean ± 1SD; 16.8±5.4 mg/dl vs. 13.8±4.6 mg/dl, p=0.008) which peaked earlier after birth (mean ± 1SD 2.9±1.6 vs. 4.3±2.3 days, p=0.007). No statistically significant difference was observed in mean weight, age at presentation, hemoglobin, reticulocyte count, TSH level, hospital stay or in the frequency of initiation of phototherapy or blood exchange between the two groups. Conclusions: We concluded that infants with G6PD c.563C \u3e T variant developed jaundice earlier than infants with normal G6PD enzyme levels. Compared to G6PD normal infants, G6PD c.563C \u3e T carrying infants had significantly low G6PD activity

The burden of anxiety and depression among patients with chronic rheumatologic disorders at a tertiary care hospital clinic in Karachi, Pakistan

Objectives: To study the burden of anxiety and depression as a comorbid among patients of chronic rheumatological disorders and to investigate possible determinants of depression and anxiety.Methods: It was a cross-sectional study conducted at the rheumatology clinic of The Aga Khan University Hospital (AKUH) Karachi, Pakistan. With convenient sampling, 111 patients who fulfilled inclusion/exclusion criteria were screened for anxiety and depression with help of Aga Khan University Anxiety and Depression Scale (AKUADS). The data was entered and analyzed by Statistical Package for Social Sciences (Version 10.0).Results: The population consisted mainly of middle aged (mean age 41) females (80.2%). The most common diagnosis was rheumatoid arthritis 57% followed by systemic lupus erythmatosis 17% and systemic sclerosis 9%. The permanent joint deformity was present in 33.3% patients and 36.9% patients were suffering from active disease with pain and inflammation. The frequency of anxiety and depression was 65.8%. Educational qualification, permanent joint deformity, active inflammation and time elapsed since diagnosis had significant association with anxiety and depression. Marital Status, gender, economic activity and monthly family income had no effect on the frequency of anxiety and depression.CONCLUSION: Almost two third of patients with chronic rheumatological disorders, also suffered from a concomitant mood disorder. Systematic evaluation of all patients for mood disorders and psychological distress in rheumatology clinics is highly recommended